It would involve only minor overstatement to say that when Anchorman: The Legend of Ron Burgundywas released in 2004, nobody knew who the heck Steve Carell was. Come to think of it, not many people knew who he was in the immediate aftermath of that film either. Initially only a modest hit in the US, Anchorman built its cult success slowly and steadily via repeated screenings in dorm rooms and bachelor pads. Indeed, many future Anchorman nuts were, on first viewing of the picture, surprised to discover that it features that bloke from The Office. You know. The guy everyone says is so darn nice.

Of course, you all know this. How could you not? For the past month, as Anchorman 2: The Legend Continues rises from the deep, a publicity machine has been stomping across the planet with ruthless efficiency. Unless you live in a cave. Oh, scratch that. If you live in a cave, Will Ferrell has probably called round to do a skit with the local bears.

The campaign reached its Irish zenith with a Dublin premier that suggested Nuremberg without the goose-stepping. Enforced jollity was all about. A gospel choir sang Afternoon Delight.

A day later, an exhausted numbness hangs over the hotel where we have gathered for interviews. In a moment more surreal than anything in the film, Ferrell, still clad in pyjamas, pops his head round the door and, after a bleary apology, makes his way towards his own inquisitors.

And here blinks Mr Carell. He’s not an obvious candidate for mass celebrity. Neater than the neatest button, hair crisp as a boy scout’s, he comes across very much like the friendly calm in the middle of an uncontrollable storm.

“My suitcase is in New York,” he says of his nice, neat backpack. “This is my subsidiary suitcase. The trick is to try to keep things unwrinkled.”

I think they have people in posh hotels to do that stuff for you. That’s what posh hotels are for. Right?

“Yes. They do. I should take advantage of that.”

Good grief. He really might be as nice and unpretentious as they say.

So, what on earth did he make of that hoopla last night? Armistices have been celebrated with less furore.

“It was so great. Everyone was so happy,” he says. “There’s such goodwill for this movie. Anything that makes people so joyous can’t be all bad. And it makes all of us happy. The first one was a genuine phenomenon, in that nobody saw it coming. It was a little movie that we all did; it was one of the first films I ever did. So I was ecstatic to be in a movie at all. And to work with those guys and become friends?”

So we’re not overstating the situation? Anchorman: The Legend of Ron Burgundy – a very funny, very chaotic send up of TV news in the 1970s – really didn’t much register on its first tour of cinemas?

“There was almost no theatrical life,” he nods. “It did okay in the US. It wasn’t a big hit or anything. It didn’t play in very many places. I’m not even sure if it was released anywhere else. This time around we have this huge promotional push. In the US, the film is everywhere. And almost in spite of that people are very genuine, very earnest in their desire to see it. It’s such a silly, dumb, ridiculous movie. It’s so strange to talk about it in any kind of serious way. It’s hard to deconstruct the success of Anchorman.”

Well, let’s give it a go. The new film finds the team coming together again to work on a 24-hour news station in the 1980s. As before, we get to laugh at some cleverly constructed characters whose comic flaws are easy to grasp. Ferrell’s Burgundy is pompous and dumb. David Koechner’s Champ is a right-wing nut who may be a closeted homosexual. Carell’s Brick is an idiot.

So those dynamics work well enough. But the budding franchise would never have got where it was without a stonking series of one-liners that gradually became stubborn catchphrases. Many were bellowed round the premiere in the style of totalitarian indoctrination techniques. Carell remembers one of Brick’s lines – “Loud Noises!” – turning up in the most unusual circumstance.

“It was years later before I realised it had become a thing,” he says of the film’s slow build. “When you say lines in a movie, you don’t think that they’re catchphrases. They’re just stupid things that you say. We had no idea that any of those lines would pop out as T-shirt slogans. Then, a couple of years ago, during Wimbledon there was a quiet moment. Then one of the fans in the stand yelled: ‘Loud noises!’ And when I heard that, I swelled with pride. Something I said made it to an international sporting event.”

Only a jerk would begrudge Carell that proud swelling. He’s worked hard for success. And it didn’t come fast. Raised in a respectable Massachusetts family – it’s said an uncle helped invent the cathode-ray tube – he went on to study history at Denison University, a liberal arts college in Ohio. When not learning about the corn laws, he fell in with a student comedy troupe and found the straight life drifting away.

“My parents were actually the ones who suggested I become an actor,” he says. “Like most people I feel incredibly indebted to my parents. They sent me to great schools. I felt like I owed them a respectable career. But when I told them that they shook their heads and said: ‘That’s not what we want. We want you to be happy.’ We had a really long talk about it. We kind of made a list of all the things I’d really enjoyed doing in my life. I was a history major and I had applied for law school. But my heart wasn’t in it. And they knew that.”

Yet there was no background of performance in his smart family?

“I’m the lone performer in the family. But I didn’t ever think that it was something I’d be doing either. It didn’t seem like a career choice to me.”

It sounds as if his folks are every bit as nice as their son. It would be pleasant to report that he immediately set any lingering doubts aside by grabbing instant stardom. This was not the case.

“It’s been incremental,” he agrees. “But the steps have got bigger along the way. There was never one big break. It was a whole lot of things.”

Interestingly, when pressed to mention one gig that really changed things, he goes further back than securing the lead role in the US version of The Office. He really lights up when he remembers getting drafted into the hugely influential Chicago comedy company Second City more than a decade earlier. This is the group that has, over the years, given us Alan Arkin, Dan Aykroyd, Mike Myers and Tina Fey. Second City seems to produce proper actors – men and women who create real characters – rather than stand-up comics and joke merchants.

“The people I’m drawn to in comic terms aren’t necessarily at the forefront of the action,” Carell muses. “They might be on the periphery. Even the silly humour I like has an element of dryness. I think most comedic actors look up to Peter Sellers. You could watch his character’s brain working. He had a way of making really broad characters completely believable. He could do more with a silence than anyone. There’s an art to that that people often forget about. So much comedy happens in the silence and the moments between.”

This really does go some way to summing up the Carell aesthetic. Even when he’s playing the lead, he comes across as an attendant player who has accidentally found himself at the foot of the stage. Think Michael Scott (the American David Brent) in The Office. Think Dan Burns in the more serious Dan in Real Life.

If reports are to be believed, Carell continues that low-key existence in normal life. I’ve read that he and his wife, Nancy, run a general store at home in Marshfield Hills, Massachusetts. Now that’s so normal, it’s positively weird. I don’t imagine Kanye West has to check the cat food stock when he’s not out doing what he normally does.

“I don’t really do that,” he says. “I stop by and get something out of the cooler. My sister-in-law runs it. It was an old general store back home in Massachusetts. I had no interest in acquiring a general store. But it was this great old store that stocked everything.”

Unlike Ron Burgundy, who, in a funny pastiche of an indestructible Hollywood cliché, spends much of Anchorman 2 missing his son’s piano recital, Steve Carell seems to have been there for every recorder concert and nativity play involving his two kids.

“I didn’t want to be an absentee parent. I wanted to be the guy that drove his kids to school every day,” he says. “Even when I was doing The Office, I rarely worked out of town. I’ve never missed any school events. That’s the feather in my cap. I’ve loved every age they’ve been. Every age my kids have been I think it’s the perfect age.”

Next year we get to see Carell stretching his range in Bennett Miller’s Foxcatcher. Based on a true story, the picture finds him playing John Eleuthère du Pont, a wealthy psychopath arrested for murder in 1997. Well, that ought to go some way to shattering this decent-bloke image. After Foxcatcher opens, he could spend some time busting up nightclubs and collapsing into gutters. No?

It seems not.

“The main reason I left The Office was that my kids were growing up so fast,” he continues. “That time, before they go to college and start pursuing their own lives is so fleeting. And you don’t get it back. You don’t get it back.”